The invention relates to a drive device in a medical device for driving a wire through a guide tube from a first position in which a distal end of said wire is outside an animal body to a second position in which said distal end is inside said animal body.
A device for implanting radioactive seeds in an animal body is known from Journal of Brachytherapy International 1998; 14:21-27. Therein is described a device in which under ultrasound guidance using an ultrasound probe and using a first template implant needles, hereinafter needles, are placed in a prostate gland. Under fluoroscopy the positions of the needles are checked. For every individual needle the length of the train of seeds is determined. The trains of seeds are placed into the needles with custom-made stylets. Thereafter a second template is attached to a stepping unit in the same way as the ultrasound probe. The ends of the stylets are placed in the second template at the same positions as the needles in the first template. The correct distance between the second template and the ends of the needles is established and the needles are retracted over the stylets manually.
The described method of implanting is cumbersome in that a lot of specialized and delicate tasks have to be fulfilled manually. Acting like this it is not possible to reach a high degree of accuracy in the placement of the seeds. The determination of the desired placements of the seeds can be done with very high accuracy based upon the known physics of the radioactive radiation emitted by the seeds and the geometry of the prostate gland. Such determination of desired placement usually is done by means of a computer programmed with a known therapy planning program. One such program is marketed under the trademark PLATO by Nucletron BV of the Netherlands. Nevertheless the manual placement of the seeds makes it necessary to recheck the number of seeds introduced and if necessary to introduce additional seed trains.
It is an object of the invention to provide a medical device comprising a drive device for driving a wire through a guide tube from a first position in which a distal end of said wire is outside an animal body to a second position in which said distal end is inside said animal body, said drive device comprising first and second elements rotatable relative to each other about a common axis, said first and second elements having contact surfaces, said contact surfaces in each rotational position of said first and second elements relative to each other being in contact with each other in a contact area along a common contact plane, a storage space for said wire going around said axis in said first element, said storage space along a length of it being open to said contact surface of said first element, said contact plane extending from a distance from said axis smaller than a smallest distance of said storage space from said axis to a distance from said axis greater than a largest distance of said storage space from said axis, said second element comprising a channel for said wire, said channel being open to said contact plane at a first position opposite said storage space and extending to a second position at a surface of said second element outside said contact area of said common contact plane.
It is also an object of the invention to provide such a medical device comprising a drive device that is disposable.
The invention shall now be described in more detail with the help of the accompanying drawings.
Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.